Immunohistochemical analysis of colon and prostate tumors. In separate experiments, slides were stained with either of the monoclonal anti-HIP1 antibodies 4B10 and 1B11, with similar results. (a) Low-power photomicrograph of a representative specimen from the analysis of colon cancer. There were many benign glands (lower left), which did not stain for HIP1, and there was a large well-differentiated tumor (upper right), which expressed HIP1 at high levels. (b) Histogram of immunohistochemical score distribution obtained from analysis of colon cancer slides (n = 25 patients). (c) Low-power photomicrograph of a representative sample from the prostate tumor microarray, demonstrating both the benign, large gland–forming prostatic epithelium (left) and several smaller, neoplastic glands (right). The benign epithelium did not stain for HIP1, while the neoplastic glands demonstrated moderate to high HIP1 expression. (d) Histogram of immunohistochemical score distribution (HIP1 expression) obtained for benign prostate, PIN, prostate cancer (PCa), and metastatic prostate cancer (Met) specimens. Two hundred sixteen benign, 174 PIN, 463 prostate cancer, and 136 metastatic prostate cancer specimens were analyzed. Magnification, ×100. Scale bar, 150 μm. Fifty percent of the spots were independently reviewed by a clinical pathologist (M.A. Rubin) and an oncologist (T.S. Ross), with 90% concordance of scores. In addition, the slides were read in their entirety during two independent reading sessions by D.S. Rao, T.S. Hyun, and T.S. Ross. There was 95% concordance of score assignments from these two reading sessions.